Dimensions.—Cephalis 0.04 diameter; thorax (with twenty-four transverse rings) 0.4 long, 0.15 broad at the mouth.
Habitat.—Fossil in Barbados.
2. Sethopyramis hexalactis, n. sp.
Shell thorny, of the same form as, and similar structure to, the preceding species, but differing in the spiny surface and the smaller subglobular cephalis, which bears small circular pores and an oblique conical horn twice the length. The whole surface is covered with short conical thorns.
Dimensions.—Cephalis 0.02 diameter; thorax (with twenty transverse rings) 0.25 long, 0.1 broad.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
Subgenus 2. Cephalopyramis, Haeckel, 1881, Prodromus, p. 432.
Definition.—Pyramidal shell with nine radial main beams (sometimes also eight or ten, as individual varieties).
3. Sethopyramis enneactis, n. sp. (Pl. [56], fig. 7).
Cephalopyramis enneactis, Haeckel, 1881, Prodromus et Atlas, pl. lvi. fig. 7.